Keysight N5439A - InfiniiMax III ZIF Probe Head. Box has been opened but has never been used.Bandwidth:28 GHz (typical)Tr = 20.9 psec (10%-90%, probe only with N2803A)Input ImpedanceC diff = 32 fF, C se = 48 fFR diff = 100 kΩ, R se = 50 kΩInput Voltage Range1.6 Vpp. ±0.8 V(HD2&3, <-38dB), 2.5 Vpp, ±1.25 V (HD2&3 <-34dB) (with N5440A 450 Ω ZIF tip)*0.8 Vpp. ±0.4 V(HD2&3, <-38dB), 1.6 Vpp, ±0.8 V (HD2&3 <-34dB) (with N5447A 200 Ω ZIF tip)*Note: HD (Harmonic distortion) <-38 dB is standard; < -34dB wider input range with slightly increased distortionThe N5439A ZIF probe head provides 28 GHz bandwidth in an economical replaceable tip form factor. Because of their extremely low loading, the ZIF tips can be left on the DUT as the probe head is moved from one probing site to the next.